server/change.c

   1 /*
   2  * Server-side change notification management
   3  *
   4  * Copyright (C) 1998 Alexandre Julliard
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * This library is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this library; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19  */
  20
  21 #include "config.h"
  22 #include "wine/port.h"
  23
  24 #include <assert.h>
  25 #include <fcntl.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <signal.h>
  29 #include <sys/stat.h>
  30
  31 #include "ntstatus.h"
  32 #define WIN32_NO_STATUS
  33 #include "windef.h"
  34
  35 #include "file.h"
  36 #include "handle.h"
  37 #include "thread.h"
  38 #include "request.h"
  39 #include "winternl.h"
  40
  41 #ifdef linux
  42 #ifndef F_NOTIFY
  43 #define F_NOTIFY 1026
  44 #define DN_ACCESS       0x00000001      /* File accessed */
  45 #define DN_MODIFY       0x00000002      /* File modified */
  46 #define DN_CREATE       0x00000004      /* File created */
  47 #define DN_DELETE       0x00000008      /* File removed */
  48 #define DN_RENAME       0x00000010      /* File renamed */
  49 #define DN_ATTRIB       0x00000020      /* File changed attibutes */
  50 #define DN_MULTISHOT    0x80000000      /* Don't remove notifier */
  51 #endif
  52 #endif
  53
  54 struct change
  55 {
  56     struct object  obj;      /* object header */
  57     struct fd     *fd;       /* file descriptor to the directory */
  58     struct list    entry;    /* entry in global change notifications list */
  59     int            subtree;  /* watch all the subtree */
  60     unsigned int   filter;   /* notification filter */
  61     int            notified; /* SIGIO counter */
  62     long           signaled; /* the file changed */
  63 };
  64
  65 static void change_dump( struct object *obj, int verbose );
  66 static int change_signaled( struct object *obj, struct thread *thread );
  67 static void change_destroy( struct object *obj );
  68
  69 static const struct object_ops change_ops =
  70 {
  71     sizeof(struct change),    /* size */
  72     change_dump,              /* dump */
  73     add_queue,                /* add_queue */
  74     remove_queue,             /* remove_queue */
  75     change_signaled,          /* signaled */
  76     no_satisfied,             /* satisfied */
  77     no_signal,                /* signal */
  78     no_get_fd,                /* get_fd */
  79     no_map_access,            /* map_access */
  80     no_lookup_name,           /* lookup_name */
  81     no_close_handle,          /* close_handle */
  82     change_destroy            /* destroy */
  83 };
  84
  85 static struct list change_list = LIST_INIT(change_list);
  86
  87 static void adjust_changes( int fd, unsigned int filter )
  88 {
  89 #if defined(F_SETSIG) && defined(F_NOTIFY)
  90     unsigned int val;
  91     if ( 0 > fcntl( fd, F_SETSIG, SIGIO) )
  92         return;
  93
  94     val = DN_MULTISHOT;
  95     if (filter & FILE_NOTIFY_CHANGE_FILE_NAME)
  96         val |= DN_RENAME | DN_DELETE | DN_CREATE;
  97     if (filter & FILE_NOTIFY_CHANGE_DIR_NAME)
  98         val |= DN_RENAME | DN_DELETE | DN_CREATE;
  99     if (filter & FILE_NOTIFY_CHANGE_ATTRIBUTES)
 100         val |= DN_ATTRIB;
 101     if (filter & FILE_NOTIFY_CHANGE_SIZE)
 102         val |= DN_MODIFY;
 103     if (filter & FILE_NOTIFY_CHANGE_LAST_WRITE)
 104         val |= DN_MODIFY;
 105     if (filter & FILE_NOTIFY_CHANGE_LAST_ACCESS)
 106         val |= DN_ACCESS;
 107     if (filter & FILE_NOTIFY_CHANGE_CREATION)
 108         val |= DN_CREATE;
 109     if (filter & FILE_NOTIFY_CHANGE_SECURITY)
 110         val |= DN_ATTRIB;
 111     fcntl( fd, F_NOTIFY, val );
 112 #endif
 113 }
 114
 115 /* insert change in the global list */
 116 static inline void insert_change( struct change *change )
 117 {
 118     sigset_t sigset;
 119
 120     sigemptyset( &sigset );
 121     sigaddset( &sigset, SIGIO );
 122     sigprocmask( SIG_BLOCK, &sigset, NULL );
 123     list_add_head( &change_list, &change->entry );
 124     sigprocmask( SIG_UNBLOCK, &sigset, NULL );
 125 }
 126
 127 /* remove change from the global list */
 128 static inline void remove_change( struct change *change )
 129 {
 130     sigset_t sigset;
 131
 132     sigemptyset( &sigset );
 133     sigaddset( &sigset, SIGIO );
 134     sigprocmask( SIG_BLOCK, &sigset, NULL );
 135     list_remove( &change->entry );
 136     sigprocmask( SIG_UNBLOCK, &sigset, NULL );
 137 }
 138
 139 static struct change *create_change_notification( struct fd *fd, int subtree, unsigned int filter )
 140 {
 141     struct change *change;
 142     struct stat st;
 143     int unix_fd = get_unix_fd( fd );
 144
 145     if (unix_fd == -1) return NULL;
 146
 147     if (fstat( unix_fd, &st ) == -1 || !S_ISDIR(st.st_mode))
 148     {
 149         set_error( STATUS_NOT_A_DIRECTORY );
 150         return NULL;
 151     }
 152
 153     if ((change = alloc_object( &change_ops )))
 154     {
 155         change->fd       = (struct fd *)grab_object( fd );
 156         change->subtree  = subtree;
 157         change->filter   = filter;
 158         change->notified = 0;
 159         change->signaled = 0;
 160         insert_change( change );
 161         adjust_changes( unix_fd, filter );
 162     }
 163     return change;
 164 }
 165
 166 static void change_dump( struct object *obj, int verbose )
 167 {
 168     struct change *change = (struct change *)obj;
 169     assert( obj->ops == &change_ops );
 170     fprintf( stderr, "Change notification fd=%p sub=%d filter=%08x\n",
 171              change->fd, change->subtree, change->filter );
 172 }
 173
 174 static int change_signaled( struct object *obj, struct thread *thread )
 175 {
 176     struct change *change = (struct change *)obj;
 177
 178     return change->signaled != 0;
 179 }
 180
 181 static void change_destroy( struct object *obj )
 182 {
 183     struct change *change = (struct change *)obj;
 184
 185     release_object( change->fd );
 186     remove_change( change );
 187 }
 188
 189 /* enter here directly from SIGIO signal handler */
 190 void do_change_notify( int unix_fd )
 191 {
 192     struct list *ptr;
 193
 194     /* FIXME: this is O(n) ... probably can be improved */
 195     LIST_FOR_EACH( ptr, &change_list )
 196     {
 197         struct change *change = LIST_ENTRY( ptr, struct change, entry );
 198         if (get_unix_fd( change->fd ) != unix_fd) continue;
 199         interlocked_xchg_add( &change->notified, 1 );
 200         break;
 201     }
 202 }
 203
 204 /* SIGIO callback, called synchronously with the poll loop */
 205 void sigio_callback(void)
 206 {
 207     struct list *ptr;
 208
 209     LIST_FOR_EACH( ptr, &change_list )
 210     {
 211         struct change *change = LIST_ENTRY( ptr, struct change, entry );
 212         long count = interlocked_xchg( &change->notified, 0 );
 213         if (count)
 214         {
 215             change->signaled += count;
 216             if (change->signaled == count)  /* was it 0? */
 217                 wake_up( &change->obj, 0 );
 218         }
 219     }
 220 }
 221
 222 /* create a change notification */
 223 DECL_HANDLER(create_change_notification)
 224 {
 225     struct change *change;
 226     struct file *file;
 227     struct fd *fd;
 228
 229     if (!(file = get_file_obj( current->process, req->handle, 0 ))) return;
 230     fd = get_obj_fd( (struct object *)file );
 231     release_object( file );
 232     if (!fd) return;
 233
 234     if ((change = create_change_notification( fd, req->subtree, req->filter )))
 235     {
 236         reply->handle = alloc_handle( current->process, change, req->access, req->attributes );
 237         release_object( change );
 238     }
 239     release_object( fd );
 240 }
 241
 242 /* move to the next change notification */
 243 DECL_HANDLER(next_change_notification)
 244 {
 245     struct change *change;
 246
 247     if ((change = (struct change *)get_handle_obj( current->process, req->handle,
 248                                                    0, &change_ops )))
 249     {
 250         if (change->signaled > 0) change->signaled--;
 251         release_object( change );
 252     }
 253 }